Search Results (7)

Breast Cancer (BrCa) exhibits a high phenotypic heterogeneity, leading to the emergence of aggressive clones and the development of drug resistance. Considering the BrCa heterogeneity and that metabolic reprogramming is a cancer hallmark, we selected seven BrCa cell lines with diverse subtypes to provide their comprehensive metabolome characterization: five lines commonly used (SK-Br-3, T-47D, MCF-7, MDA-MB-436, and MDA-MB-231), and two patient-derived xenografts (Hbcx39 and Hbcx9). We characterized their endometabolomes using ¹H-NMR spectroscopy. We found distinct metabolite profiles, with certain metabolites being common but differentially accumulated across the selected BrCa cell lines. High levels of glycine, lactate, glutamate, and formate, metabolites known to promote invasion and metastasis, were detected in all BrCa cells. In our experiment setting were identified unique metabolites to specific cell lines: xanthine and 2-oxoglutarate in SK-Br-3, 2-oxobutyrate in T-47D, cystathionine and glucose-1-phosphate in MCF-7, NAD⁺ in MDA-MB-436, isocitrate in MDA-MB-231, and NADP⁺ in Hbcx9. The unique and enriched metabolites enabled us to identify the metabolic pathways modulated in a cell-line-specific manner, which may represent potential candidate targets for therapeutic intervention. We believe this study may contribute to the functional characterization of BrCa cells and assist in selecting appropriate cell lines for drug-response studies. Full article

The utilization of the homogeneous (S)-2-pyrrolidine-tetrazole organocatalyst (Ley catalyst) in the self-condensation of ethyl pyruvate and cross-aldol reactions of ethyl pyruvate donor with non-enolizable pyruvate acceptors, namely the sterically hindered ethyl 3-methyl-2-oxobutyrate or the highly electrophilic methyl 3,3,3-trifluoropyruvate, is described as the key enantioselective step toward the synthesis of the corresponding biologically relevant isotetronic acids featuring a quaternary carbon functionalized with ester and alkyl groups. The transition from homogeneous to heterogeneous flow conditions is also investigated, detailing the fabrication and operation of packed-bed reactors filled with a silica-supported version of the pyrrolidine-tetrazole catalyst (SBA-15 as the matrix). Full article

Increases in longevity and obesity have led to a higher prevalence of Metabolic Syndrome (MetS) and several chronic conditions, such as hypertension. The prevalence of MetS and hypertension increases with advancing age and their detrimental effects on health can be attenuated by physical activity. Combined aerobic and resistance exercise training (CT) is recommended to maintain good health in older adults and is known to generate important metabolic adaptations. In this study we performed a metabolomics analysis, based on Hydrogen Nuclear Magnetic Resonance (1H NMR), to investigate the kinetics of changes in metabolism in non-physically active older women with MetS in response to 16 weeks of CT. A subset of women with MetS were selected from a larger randomized trial (that included men and women without MetS), with 12 participants on CT and 13 from the Control Group (CG). CT comprised walking/running at 63% of VO₂max, three times/week, and resistance training (RT), consisting of 15 repetitions of seven exercises at moderate intensity, twice/week. Serum metabolomic profile was analysed at baseline (0W), 4 (4W), 8 (8W), 12 (12W) and 16 weeks (16W) for CT or CG. Cardiorespiratory fitness, RT load, blood pressure, body composition, lipid and glycaemic profile were also assessed. After 16 weeks CT increased cardiorespiratory fitness (13.1%, p < 0.05) and RT load (from 48% in the lat pulldown to 160% in the leg press, p < 0.05), but there were no changes in MetS parameters, such as body composition (Body Mass, Body Mass Index (BMI), body fat percentage and waist circumference), blood pressure, lipid and glycaemic profile. However, we identified potential higher substrate to the tricarboxylic acid cycle (increase in 2-Oxobutyrate from 0W (0.0029 ± 0.0009) to 4W (0.0038 ± 0.0011) and 8W (0.0041 ± 0.0015), p < 0.05), followed by alterations (different from 0W, p < 0.05) in the production of ketone bodies (3-Hydroxybutyrate, 0W (0.0717 ± 0.0377) to 16W (0.0397 ± 0.0331), and Acetoacetate, 0W (0.0441 ± 0.0240) to 16W (0.0239 ± 0.0141)), which together might explain the known improvement in fatty acid oxidation with exercise. There was also a late increase in ornithine at 16W of CT. Further studies are needed to investigate the association between these metabolic pathways and clinical outcomes in this population. Full article

The inoculation of one-day-old broiler chicks with the cecal contents from a mature broiler breeder resulted in a highly diverse and uniform cecal bacterial community. CM did not affect feed consumption, weight gain, nor the richness, evenness, or diversity of the cecal bacterial community. However, the structure of the bacterial community was altered in birds fed the CM diet. Although the CM diet was formulated to contain equivalent metabolizable energy to the control diet, it contained more dietary fiber. The abundance of bacterial families, including those that are known to contain species able to metabolize fiber was altered (e.g., bacteria within the families, Methanobacteriaceae, Atopobiaceae, Prevotellaceae, Clostridiales Family XIII, Peptostreptococcaceae, and Succinivibrionaceae), and concentrations of SCFAs were higher in the ceca of birds fed the CM diet. Moreover, concentrations of isoleucine, isobutyrate, glutamate, and 2-oxoglutarate were higher, whereas concentrations of phenyllactic acid, indole, glucose, 3-phenylpropionate, and 2-oxobutyrate were lower in the digesta of chickens that were fed CM. The metabolic profiles of pancreas, liver, and breast muscle tissues of birds fed the CM diet differed from control birds. Metabolites that were associated with energy production, protection against oxidative stress, and pathways of amino acid and glycerophospholipid metabolism had altered concentrations in these tissues. Some of the observed changes in metabolite levels may indicate an increased disease risk in birds fed the CM diet (e.g., pancreatitis), and others suggested that birds mounted metabolic response to offset the adverse impacts of CM (e.g., oxidative stress in the liver). Full article

2-Oxobutyrate (2-OBA), as a toxic metabolic intermediate, generally arrests the cell growth of most microorganisms and blocks the biosynthesis of target metabolites. In this study, we demonstrated that using the acetate bypass to replace the pyruvate dehydrogenase complex (PDHc) in Escherichia coli could recharge the intracellular acetyl-CoA pool to alleviate the metabolic toxicity of 2-OBA. Furthermore, based on the crystal structure of pyruvate oxidase (PoxB), two candidate residues in the substrate-binding pocket of PoxB were predicted by computational simulation. Site-directed saturation mutagenesis was performed to attenuate 2-OBA-binding affinity, and one of the variants, PoxB^F112W, exhibited a 20-fold activity ratio of pyruvate/2-OBA in substrate selectivity. PoxB^F112W was employed to remodel the acetate bypass in E. coli, resulting in l-threonine (a precursor of 2-OBA) biosynthesis with minimal inhibition from 2-OBA. After metabolic detoxification of 2-OBA, the supplies of intracellular acetyl-CoA and NADPH (nicotinamide adenine dinucleotide phosphate) used for l-threonine biosynthesis were restored. Therefore, 2-OBA is the substitute for pyruvate to engage in enzymatic reactions and disturbs pyruvate metabolism. Our study makes a straightforward explanation of the 2-OBA toxicity mechanism and gives an effective approach for its metabolic detoxification. Full article

The synthetic properties of the Thiamine diphosphate (ThDP)-dependent pyruvate dehydrogenase E1 subunit from Escherichia coli (EcPDH E1) was assessed for carboligation reactions with aliphatic ketoacids. Due to its role in metabolism, EcPDH E1 was previously characterised with respect to its biochemical properties, but it was never applied for synthetic purposes. Here, we show that EcPDH E1 is a promising biocatalyst for the production of chiral α-hydroxyketones. WT EcPDH E1 shows a 180–250-fold higher catalytic efficiency towards 2-oxobutyrate or pyruvate, respectively, in comparison to engineered transketolase variants from Geobacillus stearothermophilus (TK_GST). Its broad active site cleft allows for the efficient conversion of both (R)- and (S)-configured α-hydroxyaldehydes, next to linear and branched aliphatic aldehydes as acceptor substrates under kinetically controlled conditions. The alternate, thermodynamically controlled self-reaction of aliphatic aldehydes was shown to be limited to low levels of conversion, which we propose to be due to their large hydration constants. Additionally, the thermodynamically controlled approach was demonstrated to suffer from a loss of stereoselectivity, which makes it unfeasible for aliphatic substrates. Full article

The use of doping in sports is a global problem that affects athletes around the world. Among the different methods developed to detect doping agents in biological samples, there are antibody-based methods that need an appropriate hapten design. Steroids with a hydroxyl group can be converted to the corresponding hemisuccinates. A novel approach to the synthesis of 17β-O-hemisuccinate of the common doping agent stanozolol is described here. Acylation of stanozolol with methyl 4-chloro-4-oxobutyrate/4-dimethylaminopyridine, followed by mild alkaline hydrolysis with methanolic sodium hydroxide at room temperature, gave the simultaneous protection and deprotection of pyrazole-nitrogen atoms. The proposed new synthetic method allows the desired hemisuccinate derivative to be obtained in only two steps, and with a good total yield starting from stanozolol. Full article